Abstract: Nitrogen fertilizer is the most used and often the most
mismanaged nutrient input. Nitrogen management has tremendous
implications on crop productivity, quality and environmental
stewardship. Sufficient nitrogen is needed to optimum yield and
quality. Soil and in-season plant tissue testing for nitrogen status are
a time consuming and expensive process. Real time sensing of plant
nitrogen status can be a useful tool in managing nitrogen inputs. The
objectives of this project were to assess the reliability of remotely
sensed non-destructive plant nitrogen measurements compared to wet
chemistry data from sampled plant tissue, develop in-season nitrogen
recommendations based on remotely sensed data for improved
nitrogen use efficiency and assess the potential for determining yield
and quality from remotely sensed data. Very good correlations were
observed between early-season remotely sensed crop nitrogen status
and plant nitrogen concentrations and subsequent in-season fertilizer
recommendations. The transmittance/absorbance type meters gave
the most accurate readings. Early in-season fertilizer recommendation
would be to apply 40 kg nitrogen per hectare plus 15 kg nitrogen per
hectare for each unit difference measured with the SPAD meter
between the crop and reference area or 25 kg plus 13 kg per hectare
for each unit difference measured with the CCM 200. Once the crop
was sufficiently fertilized meter readings became inconclusive and
were of no benefit for determining nitrogen status, silage yield and
quality and grain yield and protein.
Abstract: This paper discusses the design and analysis of a
hybrid PV-Fuel cell energy system destined to power a DC load. The
system is composed of a photovoltaic array, a fuel cell, an
electrolyzer and a hydrogen tank. HOMER software is used in this
study to calculate the optimum capacities of the power system
components that their combination allows an efficient use of solar
resource to cover the hourly load needs. The optimal system sizing
allows establishing the right balance between the daily electrical
energy produced by the power system and the daily electrical energy
consumed by the DC load using a 28 KW PV array, a 7.5 KW fuel
cell, a 40KW electrolyzer and a 270 Kg hydrogen tank. The variation
of powers involved into the DC bus of the hybrid PV-fuel cell system
has been computed and analyzed for each hour over one year: the
output powers of the PV array and the fuel cell, the input power of
the elctrolyzer system and the DC primary load. Equally, the annual
variation of stored hydrogen produced by the electrolyzer has been
assessed. The PV array contributes in the power system with 82%
whereas the fuel cell produces 18%. 38% of the total energy
consumption belongs to the DC primary load while the rest goes to
the electrolyzer.
Abstract: Semiconductor crystals smaller than about 10 nm,
known as quantum dots, have properties that differ from large
samples, including a band gap that becomes larger for smaller
particles. These properties create several applications for quantum
dots. In this paper new shapes of quantum dot arrays are used to
enhance the photo physical properties of gold nano-particles. This
paper presents a study of the effect of nano-particles shape, array, and
size on their absorption characteristics.
Abstract: Enterococci are important inhabitants of the animal
intestine and are widely used in probiotic products. A probiotic strain
is expected to possess several desirable properties in order to exert
beneficial effects. Therefore, the objective of this study was to
isolate, characterize and identify Enterococcus sp. from chicken cecal
and fecal samples to determine potential probiotic properties.
Enterococci were isolated from chicken ceca and feces of thirty three
clinically healthy chickens from a local farm. In vitro studies were
performed to assess antibacterial activity of the isolated LAB (using
agar well diffusion and cell free supernatant broth technique against
Salmonella enterica serotype Enteritidis), survival in acidic
conditions, resistance to bile salts, and their survival during simulated
gastric juice conditions at pH 2.5. Isolates were identified by
biochemical carbohydrate fermentation patterns using an API 50
CHL kit and API ZYM kits and by sequenced 16S rDNA. An isolate
belonging to E. faecium species exhibited inhibitory effect against S.
enteritidis. This isolate producing a clear zone as large as 10.30 mm
or greater and was able to grow in the coculture medium and at the
same time, inhibited the growth S. enteritidis. In addition, E. faecium
exhibited significant resistance under highly acidic conditions at pH
2.5 for 8 h and survived well in bile salt at 0.2% for 24 h and showing
ability to survive in the presence of simulated gastric juice at pH 2.5.
Based on these results, E. faecium isolate fulfills some of the criteria
to be considered as a probiotic strain and therefore, could be used as a
feed additive with good potential for controlling S. Enteritidis in
chickens. However, in vivo studies are needed to determine the safety
of the strain.
Abstract: This research has been conducted to study the method
of culture and comparing growth and biomass of Gracilaria corticata
cultured on rope and net for 50 days through two treatments (first
treatment: culture of alga on net and the second treatment: culture of
alga on rope and each treatment was repeated by four cases). During
culture period, the water of aquariums was replaced once every two
days for 40-50%. Also, 0.3-0.5 grams of urea fertilizer was added to
the culture environment for fertilization. Moreover, some of the
environmental factors such as pH, salinity and temperature of the
environment were measured on a daily basis. During the culture
period, extent of longitudinal growth of the species of both treatments
was equal. The said length was reached from 8-10 cm to 10.5-13 cm
accordingly. The resulted weight in repetitions of the first treatment
was higher than that of the second treatment in such a way as in the
first treatment, its weight reached from 10 grams to 21.119 grams and
in the second treatment, its weight reached from 10 grams to 17.663
grams. On a whole, it may be stated that that kind of alga being
studied has a considerable growth with respect to its volume. The
results have revealed that the percentage of daily growth and wet
weight at the end of the first treatment was higher than that of the
second treatment and it was registered as 0.934, 6.072 and 811.432 in
the first treatment and 0.797, 4.990 and 758.071 in the second
treatment respectively. This difference is significant (P
Abstract: Meeting the growth in demand for digital services
such as social media, telecommunications, and business and cloud
services requires large scale data centres, which has led to an increase
in their end use energy demand. Generally, over 30% of data centre
power is consumed by the necessary cooling overhead. Thus energy
can be reduced by improving the cooling efficiency. Air and liquid
can both be used as cooling media for the data centre. Traditional
data centre cooling systems use air, however liquid is recognised as a
promising method that can handle the more densely packed data
centres. Liquid cooling can be classified into three methods; rack heat
exchanger, on-chip heat exchanger and full immersion of the
microelectronics. This study quantifies the improvements of heat
transfer specifically for the case of immersed microelectronics by
varying the CPU and heat sink location. Immersion of the server is
achieved by filling the gap between the microelectronics and a water
jacket with a dielectric liquid which convects the heat from the CPU
to the water jacket on the opposite side. Heat transfer is governed by
two physical mechanisms, which is natural convection for the fixed
enclosure filled with dielectric liquid and forced convection for the
water that is pumped through the water jacket. The model in this
study is validated with published numerical and experimental work
and shows good agreement with previous work. The results show that
the heat transfer performance and Nusselt number (Nu) is improved
by 89% by placing the CPU and heat sink on the bottom of the
microelectronics enclosure.
Abstract: The concentrations of cadmium and lead in sewage
sludge samples were determined by Atomic Absorption
Spectrometric Method. Samples of sewage sludge were obtained
from three sewage treatment plants localised in Middle Region of
Libya (Misrata, Msallata and Tarhünah cities).
The results shows that, the mean levels of Cadmium for all regions
are ranges from 81 to 123.4 ppm and these values are higher than the
limitations for the international standard which are not registered
more than 50 ppm (dry weight) in USA, Egypt and the EU countries.
While, the lead concentrations are ranged from 8.0 to 189.2 ppm and
all values are within the standard limits which graduated between
(275–613) ppm.
Abstract: Fungal mutant strains have produced cellulase and
xylanase enzymes, and have induced high hydrolysis with enhanced
of rice straw. The mutants were obtained by exposing Penicillium
strain to UV-light treatments. Screening and selection after treatment
with UV-light were carried out using cellulolytic and xylanolytic
clear zones method to select the hypercellulolytic and
hyperxylanolytic mutants. These mutants were evaluated for their
cellulase and xylanase enzyme production as well as their abilities for
biodegradation of rice straw. The mutant 12 UV/1 produced 306.21%
and 209.91% cellulase and xylanase, respectively, as compared with
the original wild type strain. This mutant showed high capacity of
rice straw degradation. The effectiveness of tested mutant strain and
that of wild strain was compared in relation to enhancing the
composting process of rice straw and animal manures mixture. The
results obtained showed that the compost product of inoculated
mixture with mutant strain (12 UV/1) was the best compared to the
wild strain and un-inoculated mixture. Analysis of the composted
materials showed that the characteristics of the produced compost
were close to those of the high quality standard compost. The results
obtained in the present work suggest that the combination between
rice straw and animal manure could be used for enhancing the
composting process of rice straw and particularly when applied with
fungal decomposer accelerating the composting process.
Abstract: This paper addresses the issue of the autonomous
mobile robot (AMR) navigation task based on the hybrid control
modes. The novel hybrid control mode, based on multi-sensors
information by using the fuzzy approach, has been presented in this
research. The system operates in real time, is robust, enables the robot
to operate with imprecise knowledge, and takes into account the
physical limitations of the environment in which the robot moves,
obtaining satisfactory responses for a large number of different
situations. An experiment is simulated and carried out with a pioneer
mobile robot. From the experimental results, the effectiveness and
usefulness of the proposed AMR obstacle avoidance and navigation
scheme are confirmed. The experimental results show the feasibility,
and the control system has improved the navigation accuracy. The
implementation of the controller is robust, has a low execution time,
and allows an easy design and tuning of the fuzzy knowledge base.
Abstract: Poly vinyl acetate (PVA)-based titania (TiO2)–carbon
nanotube composite nanofibers (PVA-TCCNs) with various
PVA-to-solvent ratios and PVA-based TiO2 composite nanofibers
(PVA-TN) were synthesized using an electrospinning process,
followed by thermal treatment. The photocatalytic activities of these
nanofibers in the degradation of airborne monocyclic aromatics under
visible-light irradiation were examined. This study focuses on the
application of these photocatalysts to the degradation of the target
compounds at sub-part-per-million indoor air concentrations. The
characteristics of the photocatalysts were examined using scanning
electron microscopy, X-ray diffraction, ultraviolet-visible
spectroscopy, and Fourier-transform infrared spectroscopy. For all the
target compounds, the PVA-TCCNs showed photocatalytic
degradation efficiencies superior to those of the reference PVA-TN.
Specifically, the average photocatalytic degradation efficiencies for
benzene, toluene, ethyl benzene, and o-xylene (BTEX) obtained using
the PVA-TCCNs with a PVA-to-solvent ratio of 0.3 (PVA-TCCN-0.3)
were 11%, 59%, 89%, and 92%, respectively, whereas those observed
using PVA-TNs were 5%, 9%, 28%, and 32%, respectively.
PVA-TCCN-0.3 displayed the highest photocatalytic degradation
efficiency for BTEX, suggesting the presence of an optimal
PVA-to-solvent ratio for the synthesis of PVA-TCCNs. The average
photocatalytic efficiencies for BTEX decreased from 11% to 4%, 59%
to 18%, 89% to 37%, and 92% to 53%, respectively, when the flow
rate was increased from 1.0 to 4.0 L min1. In addition, the average
photocatalytic efficiencies for BTEX increased 11% to ~0%, 59% to
3%, 89% to 7%, and 92% to 13%, respectively, when the input
concentration increased from 0.1 to 1.0 ppm. The prepared
PVA-TCCNs were effective for the purification of airborne aromatics
at indoor concentration levels, particularly when the operating
conditions were optimized.
Abstract: In this paper, reliable consensus of multi-agent systems
with sampled-data is investigated. By using a suitable
Lyapunov-Krasovskii functional and some techniques such as
Wirtinger Inequality, Schur Complement and Kronecker Product, the
results of such system are obtained by solving a set of Linear Matrix
Inequalities (LMIs). One numerical example is included to show the
effectiveness of the proposed criteria.
Abstract: In this study, we compare the profiles of transitory
hybrid entrepreneurs and persistent hybrid entrepreneurs to determine
how they differ. Hybrid entrepreneurs (HEs) represent a significant
share of entrepreneurial activity yet little is known about them. We
define HEs as individuals who are active as entrepreneurs but do no
support themselves primarily by their enterprise. Persistent HEs
(PHEs) are not planning to transition to fulltime entrepreneurship
whereas transitory HEs (THEs) consider it probable. Our results
show that THEs and PHEs are quite similar in background. THEs are
more interested in increasing their turnover than PHEs, as expected,
but also emphasize self-fulfillment as a motive for entrepreneurship
more than PHEs. The clearest differences between THEs and PHEs
are found in their views on how well their immediate circle supports
full-time entrepreneurship, and their views of their own
entrepreneurial abilities and the market potential of their firm. Our
results support earlier arguments that hybrids should be considered
separately in research on entrepreneurial entry and self-employment.
Abstract: The paper deals with behaviour of the segment 50+ in
the financial market in the Czech Republic. This segment could be
said as the strong market power and it can be a crucial business
potential for financial business units. The main defined objective of
this paper is analysis of the customers´ behaviour of the segment 50-
60 years in the financial market in the Czech Republic and proposal
making of the suitable marketing approach to satisfy their demands in
the area of product, price, distribution and marketing communication
policy. This paper is based on data from one part of primary
marketing research. Paper determinates the basic problem areas as
well as definition of financial services marketing, defining the
primary research problem, hypothesis and primary research
methodology. Finally suitable marketing approach to selected sub
segment at age of 50-60 years is proposed according to marketing
research findings.
Abstract: Unmanned aircraft systems (UAS) are playing
increasingly prominent roles in defense programs and defense
strategies around the world. Technology advancements have
enabled the development of it to do many excellent jobs as
reconnaissance, surveillance, battle fighters, and communications
relays. Simulating a small unmanned aerial vehicle (SUAV)
dynamics and analyzing its behavior at the preflight stage is too
important and more efficient. The first step in the UAV design is
the mathematical modeling of the nonlinear equations of motion. .
In this paper, a survey with a standard method to obtain the full
non-linear equations of motion is utilized, and then the
linearization of the equations according to a steady state flight
condition (trimming) is derived. This modeling technique is
applied to an Ultrastick-25e fixed wing UAV to obtain the valued
linear longitudinal and lateral models. At the end the model is
checked by matching between the behavior of the states of the nonlinear
UAV and the resulted linear model with doublet at the
control surfaces.
Abstract: The elastic period has a primary role in the seismic
assessment of buildings. Reliable calculations and/or estimates of the
fundamental frequency of a building and its site are essential during
analysis and design process. Various code formulas based on
empirical data are generally used to estimate the fundamental
frequency of a structure. For existing structures, in addition to code
formulas and available analytical tools such as modal analyses,
various methods of testing including ambient and forced vibration
testing procedures may be used to determine dynamic characteristics.
In this study, the dynamic properties of the 32 buildings located in
the Madinah of Saudi Arabia were identified using ambient motions
recorded at several, spatially-distributed locations within each
building. Ambient vibration measurements of buildings have been
analyzed and the fundamental longitudinal and transverse periods for
all tested buildings are presented. The fundamental mode of vibration
has been compared in plots with codes formulae (Saudi Building
Code, EC8, and UBC1997). The results indicate that measured
periods of existing buildings are shorter than that given by most
empirical code formulas. Recommendations are given based on the
common design and construction practice in Madinah city.
Abstract: This work introduces a simple device designed to
perform in-situ direct shear and sinkage tests on granular materials
as sand, clays, or regolith. It consists of a box nested within a larger
box. Both have open bottoms, allowing them to be lowered into the
material. Afterwards, two rotating plates on opposite sides of the
outer box will rotate outwards in order to clear regolith on either
side, providing room for the inner box to move relative to the plates
and perform a shear test without the resistance of the surrounding
soil. From this test, Coulomb parameters, including cohesion and
internal friction angle, as well as, Bekker parameters can be inferred.
This device has been designed for a laboratory setting, but with few
modifications, could be put on the underside of a rover for use in
a remote location. The goal behind this work is to ultimately create
a compact, but accurate measuring tool to put onto a rover or any
kind of exploratory vehicle to test for regolith properties of celestial
bodies.
Abstract: The wide use of the Internet-based applications bring many challenges to the researchers to guarantee the continuity of the connections needed by the mobile hosts and provide reliable Internet access for them. One of proposed solutions by Internet Engineering Task Force (IETF) is to connect the local, multi-hop, and infrastructure-less Mobile Ad hoc Network (MANET) with Internet structure. This connection is done through multi-interface devices known as Internet Gateways. Many issues are related to this connection like gateway discovery, handoff, address auto-configuration and selecting the optimum gateway when multiple gateways exist. Many studies were done proposing gateway selection schemes with a single selection criterion or weighted multiple criteria. In this research, a review of some of these schemes is done showing the differences, the features, the challenges and the drawbacks of each of them.
Abstract: The Cone Penetration Test (CPT) is a common in-situ
test which generally investigates a much greater volume of soil more
quickly than possible from sampling and laboratory tests. Therefore,
it has the potential to realize both cost savings and assessment of soil
properties rapidly and continuously. The principle objective of this
paper is to demonstrate the feasibility and efficiency of using
artificial neural networks (ANNs) to predict the soil angle of internal
friction (Φ) and the soil modulus of elasticity (E) from CPT results
considering the uncertainties and non-linearities of the soil. In
addition, ANNs are used to study the influence of different
parameters and recommend which parameters should be included as
input parameters to improve the prediction. Neural networks discover
relationships in the input data sets through the iterative presentation
of the data and intrinsic mapping characteristics of neural topologies.
General Regression Neural Network (GRNN) is one of the powerful
neural network architectures which is utilized in this study. A large
amount of field and experimental data including CPT results, plate
load tests, direct shear box, grain size distribution and calculated data
of overburden pressure was obtained from a large project in the
United Arab Emirates. This data was used for the training and the
validation of the neural network. A comparison was made between
the obtained results from the ANN's approach, and some common
traditional correlations that predict Φ and E from CPT results with
respect to the actual results of the collected data. The results show
that the ANN is a very powerful tool. Very good agreement was
obtained between estimated results from ANN and actual measured
results with comparison to other correlations available in the
literature. The study recommends some easily available parameters
that should be included in the estimation of the soil properties to
improve the prediction models. It is shown that the use of friction
ration in the estimation of Φ and the use of fines content in the
estimation of E considerable improve the prediction models.
Abstract: Fluid viscous damping systems are well suited for
many air vehicles subjected to shock and vibration. These damping
system work with the principle of viscous fluid throttling through the
orifice to create huge pressure difference between compression and
rebound chamber and obtain the required damping force. One
application of such systems is its use in aircraft door system to
counteract the door’s velocity and safely stop it. In exigency
situations like crash or emergency landing where the door doesn’t
open easily, possibly due to unusually tilting of fuselage or some
obstacles or intrusion of debris obstruction to move the parts of the
door, such system can be combined with other systems to provide
needed force to forcefully open the door and also securely stop it
simultaneously within the required time i.e. less than 8 seconds. In
the present study, a hydraulic system called snubber along with other
systems like actuator, gas bottle assembly which together known as
emergency power assist system (EPAS) is designed, built and
experimentally studied to check the magnitude of angular velocity,
damping force and time required to effectively open the door.
Whenever needed, the gas pressure from the bottle is released to
actuate the actuator and at the same time pull the snubber’s piston to
operate the emergency opening of the door. Such EPAS installed in
the suspension arm of the aircraft door is studied explicitly changing
parameters like orifice size, oil level, oil viscosity and bypass valve
gap and its spring of the snubber at varying temperature to generate
the optimum design case. Comparative analysis of the EPAS at
several cases is done and conclusions are made. It is found that
during emergency condition, the system opening time and angular
velocity, when snubber with 0.3mm piston and shaft orifice and
bypass valve gap of 0.5 mm with its original spring is used, shows
significant improvement over the old ones.
Abstract: This paper presents two types of microstrip bandpass
filter (BPF) at microwave frequencies. The first one is a tunable BPF
using planar patch resonators based on a varactor diode. The filter is
formed by a triple mode circular patch resonator with two pairs of
slots, in which the varactor diodes are connected. Indeed, this filter is
initially centered at 2.4 GHz; the center frequency of the tunable
patch filter could be tuned up to 1.8 GHz simultaneously with the
bandwidth, reaching high tuning ranges. Lossless simulations were
compared to those considering the substrate dielectric, conductor
losses and the equivalent electrical circuit model of the tuning
element in order to assess their effects. Within these variations,
simulation results showed insertion loss better than 2 dB and return
loss better than 10 dB over the passband. The second structure is a
BPF for ultra-wideband (UWB) applications based on multiple-mode
resonator (MMR) and rectangular-shaped defected ground structure
(DGS). This filter, which is compact size of 25.2 x 3.8 mm2, provides
in the pass band an insertion loss of 0.57 dB and a return loss greater
than 12 dB. The proposed filters presents good performances and the
simulation results are in satisfactory agreement with the
experimentation ones reported elsewhere.